Regulating device for the outlet section of a reaction propeller tube or nozzle



June 19, 1951 2,557,435

R. J. IMBERT REGULATING DEVICE FOR THE OUTLET SECTION OF REACTION PROPELLER TUBES OR NOZZLES Filed Jan, 24, 1946 Patented June 19, I951 REGULATING DEVICE FOR THE OUTLET SECTION OF A REACTION PBOPELLER TUBE OR NOZZLE Roger Jean Imbert, Paris, France, assignor to Societe Ratean (SociteAnonyme), Paris, France, a company of France, and Rene Anxionnax,

' Paris, France, jointly Application January 24, 1946, Serial No. 843,027 .In France February 6, 1945 This invention relates to a regulating device for the outlet section of a reaction propeller tube or nomle.

It is known that in vehicles, projectiles or other movable objects propelled at great speed by a reaction device, the motive gases escape rearwards at great velocity in an expansion tube or nozzle. The motive fluid may be air taking part in a thermal cycle, or it may comprise combustion gases.

In order toensure expansion of the motive gases in the most favourable conditions under difierent operating conditions, takingdnto account for example the mechanical characteristics of the compressor for the combustive air, the velocities of the movable object and the variations in specific weight of the ambient air, it is indispensable to provide means for varying the outlet section of the expansion tube or nozzle.

It has already been proposed, in the case of circular tubes for example, to use a throttle comprising a body of revolution which can be displaced longitudinally along the axis of the tube, but this device requires a throttle of relatively substantial diameter when the partial throttling takes a relatively high value, as well as a big axial displacement of the throttle. It

3 Claims. (CL 6035.5)

The operating conditions provided for a reaction device, taking into account the various obstructions above described by way of example. permit of determining the maximum and minimum flow sections of the gases onleaving the of the orifice of the tube to be :-0.866. Thus,

. when the ratio of the outlet sections to be involves an increase in the parasitic frictions of the gases by increasing the friction surfaces.

The present invention permits of very substantially reducing these disadvantages; itconsist essentially in providing a throttle comprising one or more telescopic nozzles which can be displaced along the axis of the tube.

The following description relating to the accompanying drawing, given by way of nonlimiting examples, will permit of understanding the manner of carrying the invention into effect, it being understood that the details of the drawing and of the description form part of the said invention.

Figs. 1 and 2 illustrate in section a throttle for a nozzle of known type, Fig. 1 showing the position of the throttle for maximum opening and Fig. 2 the same throttle in the position of minimum opening.

Figs. 3 and 4 illustrate a throttle made according to the invention in the two positions corresponding respectively to Figs. 1 and 2.

effected is high the maximum diameter of the throttle will be very close to that of the tube;

this will result in an increase in the frictions in the interior of the tube and. consequently, a decrease in the output of the latter.

The throttle in conformity with the invention comprises a different arrangement-am! is illustrated, in Fig. 3 in the position of maximum opening, and, in Fig. 4, in the position of minimum opening. In these figures e is the external envelope of the tube, I the body of the throttle constituted by a nozzle or tube This nozzle is connected by profiled arms a to the control rod h slidably mounted in a guide i. Referring againto the example of the maximum ratio of the outlet sections, fixed at 4 in the preceding example, the ratio ofthe outlet diameter of the tube to the outlet diameter of the throttle will be no more than V /4=0.5. The frictional surface inside the tube, and more particularly in the region where the gases have the greatest velocities will be much more reduced and the output of the tube will be correspondingly increased.

Further, if desired, the throttle may comprise several concentric nozzles in order to fractionate the throttling and thus reduce the longitudinal dimension of the device for regulating the outlet section of the tube. In this way a multistage telescopic device is obtained. Fig. 5 shows in two half sections, corresponding respectively to two diflerent operating positions a form of construction of this kind. The throttle comprises two half section and the lower half section illusconcentric nozzles 11 and I: carried respectively by the control rods hi hr mounted one inside the other. For maximum opening of the tube outlet,

- accuse 3 the nossles occupy the position illustrated in the outfromitsfrontendtoitsrearendatthesame upperhalfoftheiigure;themeanopeningoor-' responds to the position of the nonles illustrated in the lower half of the figure; the smallest opening would be obtained by displacement to the left ofthenonlejzuptothepolntwhereitextends the male 11. It is obvious that a greater number of nozzles could be provided. Arrangements an- I alogous to those described may be adapted for tubes having a cross-sectional shape which is not a circle, as, for example, an elliptical shape or, more generally, any desired shape.

Thecontrolrodorrodsofthethrottleor throttles of thetelescopic device could be driven by any appropriate device, or servo-motor, in orderto provideagivenlawofopeningtothe reaction tube.

It is obvious that the particular forms of construction described have been given only by way of examples, and they might be modified, in particular by the substitution of technical equivalents, without thereby departing from the scope of'the invention.

What I claim is:

1. In anexhaust male for jet reaction propellers, the combination of a tubular shell for conveying gas, having a rear exit aperture and a rear, frusto-conical section with an inner surface that tapers rearwardly to said aperture, at least one axially movable, frusto-conical throttling ring in said shell, having an outer surface which tapers throughout from its front end to its rear end at the same inclination as said inner surface of said shell rear section and has substantially the same diameter at its front end as has said inner surface of said shell rear section in the neighborhood of said exit aperture, so that the ring moved to maximum throttling position has the extreme forward portion of its outer surface fitting snugly against, and the remainder of its outer surface in prolongation of, said-inner'surface of said shell rear section, .means axially disposed in said shell, comprising an axially slidablc rod, for moving said ring, and an openwork rigid structure between said rod and said ring connecting the same to ther.

a '2. In an exhaust noasle for jet reaction propel-- lers, the combination of a tubular shell for conveying gas, having a rear exit aperture and a rear, frusto-conical section with an inner surface that taper rearwardly to said aperture, at least one axially movable, frusto-conical throttling ring in said shell. having an aeroi'oil axial section and an outer surface which tapers throughinclinationassaidinnermrfaoeofsaidabell rear section and has substantially the same'diameterinisfrontportionashassaidinnermrface of said shell rearsectioninthe'neighborhood outer surface fitting snugly against, and the re-' mainder of its outer surface in prolongation of,

said inner surface of said shell rear'lection. ring supportingmembers fast with said ring, arranged in spaced-apart radial planes with respect to'aaid ring, and an axially slidable member, fast with said ring supporting members to connect the same together, for controlling bodily axial movement? ofsaid ring.

' Room .nmz runner.

REFERENCES Cll'll) The following references are of record in theills of this patent:

' UNITED B'IA'I'IB PA'IIN'I'B Number Name Date 858,588 Belling Sept. 25,- 1900 2. 58.557 Anxionnas Aug. 22. 1944 2,408,099 Sherman Sept. 24, 19 

